Multiple electrode vectors for implantable cardiac treatment devices

• US 20050049644A1
• Filed: 07/27/2004
• Published: 03/03/2005
• Est. Priority Date: 11/21/2001
• Status: Active Grant

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Bardy, Gust H., Warren, Jay A.
• Granted Patent: US 7,392,085 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/276 Protection against electrode failure
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/304 Switching circuits
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting

Abstract

The implantable cardiac treatment system of the present invention is capable of choosing the most appropriate electrode vector to sense within a particular patient. In certain embodiments, the implantable cardiac treatment system determines the most appropriate electrode vector for continuous sensing based on which electrode vector results in the greatest signal amplitude, or some other useful metric such as signal-to-noise ratio (SNR). The electrode vector possessing the highest quality as measured using the metric is then set as the default electrode vector for sensing. Additionally, in certain embodiments of the present invention, a next alternative electrode vector is selected based on being generally orthogonal to the default electrode vector. In yet other embodiments of the present invention, the next alternative electrode vector is selected based on possessing the next highest quality metric after the default electrode vector. In some embodiments, if analysis of the default vector is ambiguous, the next alternative electrode vector is analyzed to reduce ambiguity.

Claims

1. An implantable electrical cardiac treatment device comprising:

first, second, and third electrodes, the second electrode provided at a first distance from the first electrode along a lead assembly, the third electrode provided at a second distance from the first electrode along a lead assembly; and

operational circuitry electrically coupled to the first, second and third electrodes such that sensing can be performed using any pair chosen therefrom;

wherein the operational circuitry is adapted to perform the following steps;

observe a signal metric between at least two of the following sensor pairs;

first-second, first-third, and second-third;

select a default sensor pair for use in cardiac signal analysis by determining which pair performs the best as measured by the signal metric.

2. The device of claim 1, wherein the first electrode is a housing electrode.

3. The device of claim 1, wherein the operational circuitry is adapted to perform the following steps:

perform data analysis of sensed cardiac signals;

determine whether the default sensor pair is providing a suitable signal for cardiac signal analysis; and

if not, selecting a different sensor pair for use in cardiac signal analysis.

4. The device of claim 1, wherein the operational circuitry is adapted to provide an output signal using one of the electrode pairs.

5. The device of claim 1, further comprising a fourth electrode disposed as part of the lead assembly, the fourth electrode being a coil electrode, wherein the operational circuitry is configured to provide an output signal using the first electrode and the fourth electrode.

6. The device of claim 5, wherein the operational circuitry is adapted to consider electrode pairs including the fourth electrode and any of the first, second and third electrodes when performing the steps of observing a signal metric and selecting a default electrode pair.

7. The device of claim 1, wherein the operational circuitry is adapted to perform the following data analysis:

analyzing a first signal captured from the default electrode pair to determine whether;

a normal sinus rhythm has been sensed;

an arrhythmia has been sensed;

or

ambiguity is present; and

if ambiguity is present, selecting a second electrode pair using the signal metric and analyzing a second signal captured from the second electrode pair.

8. The device of claim 7, wherein the operational circuitry is adapted such that the second signal temporally corresponds to at least part of the first signal.

16. The method of claim 7, wherein the step of implanting an implantable electrical cardiac treatment device and associated lead assembly into a patient includes disposing the lead electrode assembly such that the first, second, and third electrodes define at least two generally orthogonal sensing vectors.

17. The method of claim 16, wherein the lead electrode assembly is disposed such that two sensing vectors create at an angle such that the magnitude of the cosine of the angle is less than about 0.7.

18. The method of claim 17, wherein the magnitude of the cosine of the angle is less than about 0.5.

19. The method of claim 18, wherein the magnitude of the cosine of the angle is less than about 0.3.

9. A method of cardiac signal analysis comprising:

implanting an implantable electrical cardiac treatment device and associated lead assembly into a patient such that operational circuitry housed in the device is coupled to first, second, and third electrodes;

observing a signal metric between two pairs of electrodes chosen from the first, second and third electrodes;

identifying a default electrode pair based upon observation of the signal metric; and

using the default electrode pair for sensing of cardiac signals.

10. The method of claim 9, further comprising:

determining whether the default electrode pair provides a suitable signal for cardiac signal analysis; and

if not, using a different electrode pair for sensing cardiac signals.

11. The method of claim 9, wherein one of the electrodes is provided such that it is on a housing electrode.

12. The method of claim 11, further comprising generating a cardiac stimulus using an electrode pair including the housing electrode.

13. The method of claim 9, further comprising:

performing data analysis of sensed cardiac signals;

determining whether the default sensor pair provides a suitable signal for cardiac signal analysis; and

,

if not, using a different sensor pair in cardiac signal analysis.

14. The method of claim 9, further comprising:

analyzing a first signal captured from the default electrode pair to determine whether;

a normal sinus rhythm has been sensed;

an arrhythmia has been sensed;

or

ambiguity is present; and

if ambiguity is present, selecting a second electrode pair using the signal metric and analyzing a second signal captured from the second electrode pair.

15. The method of claim 14, wherein the second signal temporally corresponds to at least part of the first signal.

20. A method of operating an implantable electrical cardiac treatment device having operational circuitry for performing cardiac performance evaluation and treatment, the method comprising:

coupling first, second, and third implanted electrodes to the operational circuitry;

observing a sensing metric for selected pairs of the implanted electrodes; and

identifying a default electrode pair for use in evaluation of cardiac signals.

21. A method as in claim 20, further comprising identifying a second best electrode pair for use in evaluation of cardiac signals.

22. A method as in claim 21, further comprising analyzing cardiac signals by:

analyzing a first signal captured using the default electrode pair to determine whether;

the first signal indicates a normal sinus rhythm;

the first signal indicates a particular arrhythmia;

or

the first signal indicates ambiguity; and

if the first signal indicates ambiguity, analyzing a second signal captured using the second best electrode pair.

23. A method of cardiac signal analysis comprising:

capturing a first signal from a first implanted electrode pair;

constructing a first template using the first signal;

capturing a second signal from a second implanted electrode pair;

constructing a second template using the second signal; and

capturing a signal using the first and second electrode pairs and using the first and second templates to determine whether a treatable cardiac condition exists.

24. The method of claim 23, wherein:

the first implanted electrode pair has a first sensing vector;

the second implanted electrode pair has a second sensing vector; and

the first and second sensing vectors form an angle, wherein the magnitude of the cosine of the angle is less than about 0.5.

25. An implantable cardiac treatment system comprising an implantable canister housing operational circuitry and a plurality of electrodes electrically coupled to the operational circuitry wherein the operational circuitry is configured and coupled to the electrodes to define at least a first implanted electrode pair and a second implanted electrode pair, the operational circuitry being configured to perform the steps of:

capturing a first signal from the first implanted electrode pair;

constructing a first template using the first signal;

capturing a second signal from the second implanted electrode pair;

constructing a second template using the second signal; and

capturing a signal using the first and second electrode pairs and using the first and second templates to determine whether a treatable cardiac condition exists.